Syringe

ABSTRACT

The invention provides a syringe for use in an ophthalmic injection. The syringe comprises a body, a stopper and a plunger. The body comprises an outlet at an outlet end and the stopper is arranged within the body such that a front surface of the stopper and the body define a variable volume chamber from which a fluid can be expelled though the outlet. The plunger comprises a plunger contact surface at a first end and a rod extends between the plunger contact surface and a rear portion. The plunger contact surface is arranged to contact the stopper but not couple thereto, such that the plunger can be used to force the stopper towards the outlet end of the body, reducing the volume of the variable volume chamber, but not to move the stopper away from the outlet end.

The present invention relates to a syringe, particularly to a smallvolume syringe such as a syringe suitable for ophthalmic injections. Theinvention also extends to a method of assembling such a syringe.

Many medicaments are delivered to a patient in a syringe from which theuser can dispense the medicament. If medicament is delivered to apatient in a syringe it is often to enable the patient, or a caregiver,to inject the medicament. It is important for patient safety andmedicament integrity that the syringe and the contents of that syringeare sufficiently sterile to avoid infection, or other, risks forpatients. Sterilisation can be achieved by terminal sterilisation inwhich the assembled product, typically already in its associatedpackaging, is sterilised using heat or a sterilising gas.

For small volume syringes, for example those for injections into the eyein which it is intended that less than about 0.1 ml of liquid is to beinjected, the sterilisation can pose difficulties that are notnecessarily associated with larger syringes. Changes in pressure,internal or external to the syringe, can cause parts of the syringe tomove unpredictably, which may alter sealing characteristics andpotentially compromise sterility. Incorrect handling, includingassembly, of the syringe can also pose risks to product sterility.

The present invention provides a syringe, the syringe comprising a body,a stopper and a plunger, the body comprising an outlet at an outlet endand the stopper being arranged within the body such that a front surfaceof the stopper and the body define a variable volume chamber from whicha fluid can be expelled though the outlet, the plunger comprising aplunger contact surface at a first end and a rod extending between theplunger contact surface and a rear portion, the plunger contact surfacearranged to contact the stopper but not couple thereto, such that theplunger can be used to force the stopper towards the outlet end of thebody, reducing the volume of the variable volume chamber, but not tomove the stopper away from the outlet end.

Providing a plunger which does not couple to the stopper reduces thechances for incorrect handling of the syringe as the plunger can bewithdrawn from the syringe without movement of the stopper away from theoutlet end. This prevents a user from accidentally moving the plunger(and therefore a stopper connected thereto) and causing non-sterile air(or other fluid) to be drawn into the syringe, or causing movement ofthe stopper to a non-sterile area. It has also been found that creatinga connection between a plunger to a stopper during assembly, using forexample a screwing action or a push-fit action, can distort the stopperin an unpredictable manner which may compromise the sealing and/orsterility of the final product, or may increase pressure in the variablevolume chamber which could cause fluid leakage from the outlet end.

The body of the syringe may be a substantially cylindrical shell, or mayinclude a substantially cylindrical bore with a non-circular outershape. The outlet end of the body includes an outlet through which afluid housed within the variable volume chamber can be expelled as thevolume of said chamber is reduced. The outlet may comprise a projectionfrom the outlet end through which extends a channel having a smallerdiameter than that of the variable volume chamber. The outlet may beadapted, for example via a luer lock type connection, for connection toa needle or other accessory such as a sealing device which is able toseal the variable volume chamber, but can be operated, or removed, tounseal the variable chamber and allow connection of the syringe toanother accessory, such as a needle. Such a connection may be madedirectly between the syringe and accessory, or via the sealing device.The body extends along a first axis from the outlet end to a rear end.

The body may be made from a plastic material or from glass, or from anyother suitable material and may include indicia on a surface thereof toact as an injection guide.

The stopper may be made from rubber, silicone or other suitableresiliently deformable material. The stopper provides a sealing functionby defining the rear of the variable volume chamber with a fluid tightseal which also provides a sterility seal. The stopper may besubstantially cylindrical and the stopper may include one or morecircumferential ribs around an outer surface of the stopper, the stopperand ribs being dimensioned such that the ribs form a substantially fluidtight seal with an internal surface of the syringe body. The frontsurface of the stopper may be any suitable shape, for examplesubstantially planar, or substantially conical. The stopper may besubstantially solid or may include recesses. The rear surface of thestopper may include a substantially central recess which may be anyshape provided the sealing function of the stopper is not compromised.Said central recess may be substantially cylindrical in shape or saidcentral recess may include an initial bore having a first diameter, theinitial bore leading from the rear surface into the stopper to an innerrecess having a second diameter, the second diameter being larger thanthe first diameter. Such a central recess could be used to connect aplunger to the stopper using a snap fit feature in a known manner. Sucha design allows a substantially standard stopper design to be used andthis can reduce the parts cost for the syringe. Also, it is noted thatremoving material from the central portion of the stopper, where it isnot needed for the stopper to function as required, reduces the stopperweight and reduces the amount of material needed to manufacture thestopper. The stopper may be substantially rotationally symmetric aboutan axis through the stopper.

The plunger comprises a plunger contact surface and extending from thata rod extends from the plunger contact surface to a rear portion. Therear portion may include a user contact portion adapted to be contactedby a user during an injection event. The user contact portion maycomprise a substantially disc shaped portion, the radius of the discextending substantially perpendicular to the axis along which the rodextends. The user contact portion could be any suitable shape. The axisalong which the rod extends may be the first axis, or may besubstantially parallel with the first axis.

The plunger contact surface is adapted to make contact with the rearsurface of the stopper, but not couple thereto. The plunger contactsurface may be substantially planar and may be substantially circular inshape. The plunger contact surface may be substantially circular with anouter diameter less than the internal diameter of the body. The diameterof the plunger contact surface may be substantially equal to thediameter of the rear surface of the stopper with which it is to makecontact. The plunger contact surface may be adapted to present asubstantially rotationally symmetrical surface to the rear surface ofthe stopper as this assists in providing a repeatable and evenlydistributed force to the stopper during use which can help to preventdistortions. The plunger contact surface may not be planar and maycomprise an annular contact surface to contact the stopper at oradjacent an out edge thereof. The plunger contact surface may comprise aplurality of arms which extend from the plunger rod to make contact withthe stopper. The plunger contact surface may be substantiallyrotationally symmetrical in any of the above, or other, embodiments.

The rod may have a round or cross-form cross-section. A cross-form crosssection may be formed from ribs extending along at least part of therod. The ribs may extend substantially parallel with the axis alongwhich the rod extends. The cross-form cross section provides rigidity tothe rod without significantly increasing manufacturing complexity.

The rod may be manufactured from any suitable material, or combinationof materials, and in one embodiment is made from a plastic material. Therod may be substantially rigid under expected use conditions. Althoughsome flexing of the materials in the plunger is unavoidable in a bulkmanufactured product, it is advantageous that the rod cannot flexsignificantly during use, particularly for low volume, accurate,injections as any flexing could lead to unpredictable dosing results.

The syringe may include a backstop arranged at a rear portion of thebody. The backstop may be removable from the syringe. If the syringebody includes terminal flanges at the end opposite the outlet end thebackstop may be configured to substantially sandwich terminal flanges ofthe body as this prevent movement of the backstop in a directionparallel to the first axis.

The rod may comprise at least one rod shoulder directed away from theoutlet end and the backstop may include a backstop shoulder directedtowards the outlet end to cooperate with the rod shoulder tosubstantially prevent movement of the rod away from the outlet end whenthe backstop shoulder and rod shoulder are in contact. Restriction ofthe movement of the rod away from the outlet end can help to maintainsterility during terminal sterilisation operations, or other operationsin which the pressure within the variable volume chamber or outside thechamber may change. During such operations any gas trapped within thevariable volume chamber, or bubbles that may form in a liquid therein,may change in volume and thereby cause the stopper to move. Movement ofthe stopper away from the outlet could result in the breaching of asterility zone created by the stopper. This is particularly importantfor low volume syringes where there are much lower tolerances in thecomponent sizes and less flexibility in the stopper. The term sterilityzone as used herein is used to refer to the area within the syringe thatis sealed by the stopper from access from either end of the syringe.This may be the area between a seal of the stopper, for example acircumferential ridge, closest to the outlet and a seal of the stopper,for example a circumferential ridge, furthest from the outlet. Thedistance between these two seals defines the sterility zone of thestopper since the stopper is installed into the syringe barrel in asterile environment.

As noted above, a terminal sterilisation process may be used tosterilise the complete article and such a process may use a knownprocess such as an Ethylene Oxide or a Hydrogen Peroxide sterilisationprocess.

The inclusion of one or more circumferential ribs on the stopper canalter the force required to cause the stopper to move from a stationaryposition and can also alter the sealing properties of the stopper. Tofurther assist in maintaining sterility during the operations notedabove the stopper may comprise at least a front circumferential rib anda rear circumferential rib and those ribs may be separated in adirection along the first axis by at least 3 mm, by at least 3.5 mm, byat least 3.75 mm or by 4 mm or more. One or more additional ribs (forexample 2, 3, 4 or 5 additional ribs, or between 1-10, 2-8, 3-6 or 4-5additional ribs) may be arranged between the front and rear ribs. In oneembodiment there are a total of three circumferential ribs.

A stopper with such an enhanced sterility zone can also provideprotection for the injectable medicament during a terminal sterilisationprocess. Some medicaments, example a biological medicament, could bedamaged by exposure to Ethylene Oxide. More ribs on the stopper, or agreater distance between the front and rear ribs, can reduce thepotential exposure of the medicament to the sterilising agent.

The rod shoulder may be arranged within the external diameter of therod, or may be arranged outside the external diameter of the rod. Byproviding a shoulder that extends beyond the external diameter of therod, but still fits within the body, the shoulder can help to stabilisethe movement of the rod within the body by reducing movement of the rodperpendicular to the first axis. The rod shoulder may comprise anysuitable shoulder forming elements on the rod, but in one embodiment therod shoulder comprises a substantially disc shaped portion on the rod.

In one embodiment of the syringe, when arranged with the plunger contactsurface in contact with the stopper and the variable volume chamber isat its intended maximum volume there is a clearance of no more thanabout 2 mm between the rod shoulder and backstop shoulder. In someembodiments there is a clearance of less than about 1.5 mm and in someless than about 1 mm. This distance is selected to substantially limitor prevent excessive rearward (away from the outlet end) movement of thestopper.

In one embodiment the variable volume chamber has an internal diametergreater than 5 mm or 6 mm and less than 3 mm or 4 mm. The internaldiameter may be between 3 mm and 6 mm, or between 4 mm and 5 mm. Inanother embodiment the syringe is dimensioned so as to have a nominalmaximum fill volume of volume of between about 0.25 ml and 0.75 ml, orbetween 0.4 ml and 0.6 ml. The length of the body of the syringe may beless than 70 mm, less than 60 mm or less than 50 mm. In one embodimentthe length of the syringe body is between 45 mm and 50 mm, the internaldiameter is between 4 mm and 5 mm and the fill volume is between 0.1 mland 0.3 ml of liquid.

In one embodiment, the syringe is suitable for ophthalmic injections,and as such has a suitably small volume. The syringe may be adapted forophthalmic injections. The syringe may also be silicone free, orsubstantially silicone free, or may comprise a low level of silicone aslubricant. In one embodiment, the syringe may meet USP789.

The variable volume chamber of the syringe may be filled with anysuitable injectable liquid or medication, for example an injectablemedicament. In one embodiment the variable volume chamber is filled withan injectable medicament comprising an active suitable for the treatmentof an ocular disease. Examples of such ocular diseases include choroidalneovascularisation, age-related macular degeneration (both wet and dryforms), macular edema secondary to retinal vein occlusion (RVO)including both branch RVO (bRVO) and central RVO (cRVO), choroidalneovascularisation secondary to pathologic myopia (PM), diabetic macularedema (DME), diabetic retinopathy, and proliferative retinopathy. In oneembodiment, the medicament comprises a biologic active. The biologicactive may be an antibody (or fragment thereof) or a non-antibodyprotein. In one embodiment the medicament comprises a VEGF antagonist.Suitable VEGF antagonists include ranibizumab (Lucentis™), bevacizumab(Avastin™), aflibercept (Eylea™, also known as VEGF-Trap Eye),conbercept (KH902 from Chengdu Kanghong Biotechnologies Co. Ltd,described as FP3 in WO2005/121176, the contents of which are herebyincorporated by reference) and the related glycoform KH906 or pazopanib(from GlaxoSmithKline).

In one embodiment, the syringe is filled with between about 0.01 ml andabout 2 ml (for example between about 0.05 ml and about 1 ml, betweenabout 0.1 ml and about 0.5 ml) of an injectable medicament. Of course,typically a syringe is filled with more than the desired dose to beadministered to the patient, to take into account wastage due to “deadspace” within the syringe and needle. Thus, in one embodiment, thesyringe is filled with a dosage volume (i.e. the volume of medicamentintended for delivery to the patent) of between about 0.01 ml and about2 ml (e.g. between about 0.05 ml and about lml, between about 0.1 ml andabout 0.5 ml) of an injectable medicament. For example, for Lucentis,the dosage volume is 0.05 ml or 0.03 ml (0.5 mg or 0.3 mg) of a 10 mg/mlinjectable medicament solution; for Eylea, the dosage volume is 0.05 mlof a 40 mg/ml injectable medicament solution.

As noted above, when the syringe contains a medicament solution theoutlet may be reversibly sealed to maintain sterility of the medicament.This sealing may be achieved through the use of a sealing device as isknown in the art. For example the OVS™ system which is available fromVetter Pharma International GmbH. The sealing of the outlet should besuch that that sterility of the contents of the variable volume chambercan be maintained until such time as the stopper is moved to breach thesterility seal or the outlet is unsealed.

By providing a plunger that does not couple with the stopper a newmethod of assembly is made possible and so the invention furtherprovides a method of assembling a syringe, the method comprising thesteps of:

-   -   i) providing a body and a stopper, the body comprising an outlet        at an outlet end and the stopper being arranged within the body        such that a front surface of the stopper and the body define a        variable volume chamber from which a fluid can be expelled        though the outlet, the outlet being releasably sealed and the        variable volume chamber containing a medicament; and    -   ii) providing a plunger comprising a plunger contact surface at        a first end and a rod extending between the plunger contact        surface and a rear portion and arranging the plunger contact        surface and at least part of the plunger within the body without        coupling the plunger to the stopper.

The method may further comprise an additional step, step iii), offilling the variable volume chamber of the syringe, which may be filledwith any suitable injectable medicament. In one embodiment the variablevolume chamber is filled with an injectable medicament suitable for thetreatment of an ocular disease. Examples of such ocular diseases includechoroidal neovascularisation, age-related macular degeneration (both wetand dry forms), macular edema secondary to retinal vein occlusion (RVO)including both branch RVO (bRVO) and central RVO (cRVO), choroidalneovascularisation secondary to pathologic myopia (PM), diabetic macularedema (DME), diabetic retinopathy, and proliferative retinopathy. In oneembodiment, the medicament comprises a biologic active. The biologicactive may be an antibody (or fragment thereof) or a non-antibodyprotein. In one embodiment the medicament comprises a VEGF antagonist.Suitable VEGF antagonists include ranibizumab (Lucentis™), bevacizumab(Avastin™), aflibercept (Eylea™, also known as VEGF-Trap Eye),conbercept (KH902 from Chengdu Kanghong Biotechnologies Co. Ltd,described as FP3 in WO2005/121176, the contents of which are herebyincorporated by reference) and the related glycoform KH906 or pazopanib(from GlaxoSmithKline).

It should be noted that steps ii) and iii) above may be carried out ineither order. Thus the method may comprise, in sequence, steps i), ii),iii) or steps i), iii), ii) or steps iii), i), ii).

The method may further comprise a step iv) of packaging the assembledsyringe in a substantially sealed package. The method may furthercomprise a terminal sterilisation step, step v), following packaging.The terminal sterilisation step may comprise known techniques such asEthylene Oxide sterilisation of Hydrogen Peroxide sterilisation.

The invention also extends to a sealed package containing a sterilepre-filled syringe substantially as described herein.

If the rod comprises a rod shoulder as described above and the syringeincludes a removable backstop as described the backstop may be coupledto the syringe body after the plunger has been arranged in the body andthe rod shoulder is arranged between the outlet end and the backstopshoulder. By ensuring that the rod shoulder is arranged between theoutlet end and the backstop shoulder when the backstop is coupled to thedevice a complex mechanism for enabling the movement of the rod shoulderpast the backstop shoulder after coupling the backstop to the syringe isavoided.

In one embodiment step i) and iii) are carried out in a sterile, orsubstantially sterile, environment. At some point between the fillingstep and the final assembly being sealed into packaging the syringe isremoved from the sterile, or substantially sterile, environment. Aterminal sterilisation step can then be conducted on the packagedproduct.

In one embodiment of the method the plunger rod is dropped into thesyringe body. This is a simple operation and makes use of gravity ratherthan any automated assembly equipment. This is made possible because therod does not need to be manipulated or forced to couple with thestopper.

The invention also provides a plunger suitable for use in the syringe ormethod described above.

It should be understood that throughout this specification and in theclaims that follow, unless the context requires otherwise, the word“comprise”, or variations such as “comprises” or “comprising”, impliesthe inclusion of the stated integer or step, or group of integers orsteps. The term “comprising” encompasses “including” as well as“consisting” e.g. a composition “comprising” X may consist exclusivelyof X or may include something additional e.g. X+Y. It should also beunderstood that, unless not physically possible, features described inconnection with one embodiment can be used alone, or in combination withone or more features described in connection with the same embodiment orone or more other embodiments. The term “about” in relation to anumerical value x is optional and means, for example, x+/−10%.

The invention will now be further described, by way of example only,with reference to the following drawings in which:

FIG. 1 shows a side view of a syringe;

FIG. 2 shows a cross section of a top down view of a syringe;

FIG. 3 shows a view of a plunger;

FIG. 4 shows a cross section though a plunger;

FIG. 5 shows a stopper; and

FIG. 6 shows a flowchart of the assembly process.

FIG. 1 shows a view from a side of a syringe 1 comprising a body 2,plunger 4, backstop 6 and a sealing device 8.

FIG. 2 shows a cross section through the syringe 1 of FIG. 1 from above.The syringe 1 is suitable for use in an ophthalmic injection. Thesyringe 1 comprises a body 2, a stopper 10 and a plunger 4. The syringe1 extends along a first axis A. The body 2 comprises an outlet 12 at anoutlet end 14 and the stopper 10 is arranged within the body 2 such thata front surface 16 of the stopper 10 and the body 2 define a variablevolume chamber 18. The variable volume chamber 18 contains an injectablemedicament 20 comprising ranibizumab. The injectable fluid 20 can beexpelled though the outlet 12 by movement of the stopper 10 towards theoutlet end 14 thereby reducing the volume of the variable volume chamber18. The plunger 4 comprises a plunger contact surface 22 at a first end24 and a rod 26 extending between the plunger contact surface 22 and arear portion 25. The plunger contact surface 22 is arranged to contactthe stopper 10 but not couple thereto, such that the plunger 4 can beused to move the stopper 10 towards the outlet end 14 of the body 2.Such movement reduces the volume of the variable volume chamber 18 andcauses fluid therein to be expelled though the outlet. However, sincethe plunger 4 is not coupled to the stopper 10 it is not possible to usethe plunger 4 to move the stopper 10 away from the outlet end 14.

The backstop 6 is attached to the body 2 by coupling to a terminalflange 28 of the body 2. The backstop 6 includes sandwich portion 30which is adapted to substantially sandwich at least some of the terminalflange 28 of the body 2. The backstop 6 is adapted to be coupled to thebody 2 from the side by leaving one side of the backstop 6 open so thatthe backstop 6 can be fitted to the syringe 2.

The body 2 defines a substantially cylindrical bore 36 which has a boreradius. The rod 26 comprises a rod shoulder 32 directed away from theoutlet end 14. The rod shoulder 32 extends to a rod shoulder radius fromthe first axis A which is such that it slightly less than the boreradius so that the shoulder fits within the bore 36. The backstop 6includes a backstop shoulder 34 directed towards the outlet end 14. Theshoulders 32,34 are configured to cooperate to substantially preventmovement of the rod 26 away from the outlet end 14 when the backstopshoulder 34 and rod shoulder 32 are in contact. The backstop shoulder 34extends from outside the bore radius to a radius less than the rodshoulder radius so that the rod shoulder 32 cannot pass the backstopshoulder 34 by moving along the first axis A. In this case the rodshoulder 32 is substantially disc, or ring, shaped and the backstopshoulder 34 includes an arc around a rear end 38 of the body 2.

The backstop 6 also includes two finger projections 40 which extend inopposite directions away from the body 2 substantially perpendicular tothe first axis A to facilitate manual handling of the syringe 1 duringuse.

In this example the syringe comprises a 0.5 ml body 2, that is a bodywith a notional maximum fill volume of about 0.5 ml, filled with betweenabout 0.1 and 0.3 ml of an injectable medicament 20 comprising a 10mg/ml injectable solution comprising ranibizumab. The syringe body 2 hasan internal diameter of about between about 4.5 mm and 4.8 mm, a lengthof between about 45 mm and 50 mm.

The plunger 4 and stopper 10 will be described in more detail withreference to later figures.

FIG. 3 shows a perspective view of the plunger 4 of FIG. 1 showing theplunger contact surface 22 at the first end 24 of the plunger 4. The rod26 extends from the first end 24 to the rear portion 25. The rearportion 25 includes a disc shaped flange 42 to facilitate user handlingof the device. The flange 42 provides a larger surface area for contactby the user than a bare end of the rod 26.

The rod 26 comprises ribs 44 which extend along the rod 26, the ribsforming a cross-form cross section for the rod 26 as shown in moredetail in subsequent figures. The rod 26 comprises a disc shaped portion46, the disc shaped portion 46 extending radially beyond the ribs 44 andalso forming the rod shoulder 32.

The ribs 44 may be substantially solid, or may include gaps 48. The discportion 46 may be solid, or may include gaps 50. Gaps 48,50 may be usedto facilitate gas flow within the body 2 if necessary for sterilization,or other, purposes.

FIG. 4 shows a cross section though a syringe body 2 and rod 26. The rod26 includes four longitudinal ribs 44 and the angle between the ribs is90°.

FIG. 5 shows a detailed view of a stopper 10 showing a conical shapedfront surface 16 and three circumferential ribs 52,54,56 around asubstantially cylindrical body 58. The axial gap between the first rib52 and the last rib 56 is about 3 mm. The rear surface 60 of the stopper10 includes a substantially central recess 62. The central recess 62includes an initial bore 64 having a first diameter. The initial bore 64leading from the rear surface 60 into the stopper 10 to an inner recess66 having a second diameter, the second diameter being larger than thefirst diameter.

FIG. 6 shows a flow chart for the assembly of a syringe 1. In Step 1 aprefilled body 2 is provided. The prefilled body comprises a body 2filled with an injectable medicament 20 comprising ranibizumab, althoughother medicaments could be used in addition or instead, or a placebosolution could be used. A stopper 10 is arranged in the body 2 to form avariable volume chamber 18 and the outlet 12 is sealed with a sealingdevice 8.

In Step 2 a plunger 4 is arranged in the body 2. In one embodiment theplunger 4 is dropped into the body 2. This may be by gravity alone, orthe plunger may be placed into the body 2 using a machine or human andthe body then oriented so that the plunger 4 falls into the body 2 untilthe plunger contact surface 22 makes contact with the stopper 10.

In Step 3 a backstop 6 is coupled to the terminal flange 28 of the body.The backstop 6 and rod being arranged such that the rod shoulder 32 islocated between the outlet end of the body and the backstop shoulder 34.

In Step 4 the syringe is sealed into a package and in Step 5 the packageand its contents is sterilised in a terminal sterilisation process. Theterminal sterilisation process may use known process such as an EthyleneOxide or a Hydrogen Peroxide sterilisation process.

It should be understood that the invention has been described above byway of example only and that modifications in detail can be made withoutdeparting from the scope of the claims.

1-17. (canceled)
 18. A terminally sterilized, prefilled syringe forophthalmic injections, the syringe comprising a body (2), a stopper(10), and a plunger (4), wherein the body comprises an outlet (12) at anoutlet end (14); the stopper (10) is arranged within the body (2) suchthat a front surface (16) of the stopper (10) and the body (2) define avariable volume chamber (18) from which a fluid can be expelled thoughthe outlet (12); and the plunger (4) comprises a plunger contact surface(22) at a first end (24) and a rod (26) extending between the plungercontact surface (22) and a rear portion (25), wherein the syringe isfilled with a dosage volume of between about 0.01 mL and about 2 mL; theplunger contact surface (22) is arranged to contact the stopper (10) butnot couple thereto, such that the plunger (4) can be used to force thestopper (10) towards the outlet end (14) of the body (2), reducing thevolume of the variable volume chamber (18), but not to move the stopper(10) away from the outlet end (14); the syringe (1) includes a backstop(6) arranged at a rear portion of the body (2), the backstop (6)including a backstop shoulder (34) directed towards the outlet end (14)to cooperate with the rod shoulder (32) to substantially preventmovement of the plunger rod (26) away from the outlet end (14) when thebackstop shoulder (34) and rod shoulder (32) are in contact, and whenthe plunger contact surface (22) is in contact with the stopper (10) andthe variable volume chamber (18) is at its intended maximum volume,there is a clearance of no more than 2 mm between the rod shoulder (32)and the backstop shoulder (34).
 19. The syringe of claim 18, wherein thedosage volume is between about 0.05 mL and about 1 mL.
 20. The syringeof claim 18, wherein the plunger contact surface (22) is a substantiallyplanar disc, and the plunger contact surface (22) contacts a rearsurface of the stopper (10).
 21. The syringe of claim 18, wherein therod shoulder (32) is arranged within the external diameter of the rod(26).
 22. The syringe of claim 18, wherein the rod shoulder (32)comprises a substantially disc shaped portion of the rod (26).
 23. Thesyringe of claim 18, wherein the stopper (10) has one or morecircumferential ribs.
 24. The syringe as claimed in claim 23, whereinthe stopper (10) has a central recess.
 25. The syringe of claim 18,wherein the syringe is silicone free or substantially silicone free. 26.The syringe of claim 18, wherein the syringe is filled with aninjectable medicament comprising an active suitable for the treatment ofan ocular disease.
 27. The syringe of claim 26, wherein the medicamentis a VEGF antagonist.
 28. The syringe of claim 27, wherein themedicament is ranibizumab.
 29. The syringe of claim 27, wherein themedicament is aflibercept.